Electronic combination locking systems for controlling entry to safes are now widely used in vault doors and especially in small to medium size safes. Such digital combination locking systems have included, for example, individual access codes for authorized personnel to use for opening safes. Automatic recordation of entry times associated with user access codes have also been used. Ability to retrieve records of such events at a later date and automatic alarms have also been used with locking systems for safes. Examples of the art in electronically controlled locking systems can be found in U.S. Pat. Nos. 4,904,984 and 5,617,082.
However, in order to provided further security to such electronically controlled locking systems against misuse by authorized users and against burglars, continual improvement in electronically controlled locking systems is needed.
This invention provides additional security by enabling continuous monitoring of the condition of safe and vault doors or other entry doors to a secured areas without the use of a camera or closed circuit television. It is also an object of this invention to provide a relatively inexpensive and reliable door monitoring means for use with electronically controlled locks.